Resealable test tube

ABSTRACT

AN OPEN ENDED TEST TUBE INTO WHICH A RESILIENT, SEALING PLUG IS INSERTED. A U-SHAPED FLOW TUBE EEXTENDS REMOVABLY THROUGH A PAIR OF SPACED APART APERTURES IN THE PLUG AND MAINTAINS THE TEST TUBE SEALED. WITHDRAWAL OF ONE TUBE END FROM ONE OF THE APERTURES AND APPLICATION OF A NEGATIVE OR POSITITVE PRESSURE TO THE THUS OPENED APERTURE FORCES FLUID MATERIALS VIA THE FLOW TUBE INTO OR OUT OF THE TEST TUBE. THE PLUG INCLUDES MEANS FOR POSITIONING AND HOLDING THE WITHDRAWN FLOW TUBE SECTION EXTERIORLY OF THE TEST TUBE.

Dnc. 5,1972 B. w. TAYLOR RESEALABLE TEST TUBE Filed June 10, 1970 FIG 3 AIR SOURCE N TOR.

INVE BILLY WALKER TAYLOR BY W 57M ATTORI-YS United States Patent O 3,705,018 RESEALABLE TEST TUBE Billy W. Taylor, 2965 Mi Elana Circle, Walnut Creek, Calif. 94598 Filed June 10, 1970, Ser. No. 45,083 Int. Cl. G01n 1/10 US. Cl. 23-292 16 Claims ABSTRACT OF THE DISCLOSURE An open ended test tube into which a resilient, sealing plug is inserted. A U-shaped flow tube extends removably through a pair of spaced apart apertures in the plug and maintains the test tube sealed. Withdrawal of one tube end from one of the apertures and application of a negative or positive pressure to the thus opened aperture forces fluid materials via the flow tube into or out of the test tube. The plug includes means for positioning and holding the withdrawn flow tube section exteriorly of the test tube.

BACKGROUND OF THE INVENTION Today an ever increasing number of laboratory tests, particularly blood tests, is performed. Such tests require a multitude of steps during which a blood sample must be handled prior to and during the actual test or tests. Ordinarily specialized laboratories handle large numbers of tests for a given geographic area. Efficiency in the handling of the samples is necessary to prevent the cost of laboratory tests from spiraling and, hopefully, to enable an actual cost reduction. Moreover, safety precautions should be observed that prevent a contamination of the sample and prevent the sample from contaminating the atmosphere and representing-a health hazard to the laboratory personnel.

Presently the handling of the sample and frequently the actual testing are manually performed. The blood sample is placed in a test tube, the red blood cells are separated and serum is then withdrawn from the test tube and placed in a plurality of containers for circulation to the various testing stations. Serum withdrawal is manually performed by pouring or with the help of syringes or the like. This is time consuming and tedious Work, may disturb the separation of the serum and the cells and can, therefore, render subsequent tests useless unless the technician withdrawing the serum is skillful and exercises a high degree of care. Moreover, the sample is not sealed. Diseased samples can contaminate the surroundings and present, therefore, a health hazard to technicians and other personnel who come in contact with it.

This substantially universally practiced method of handling samples in laboratories is difiicult to automate under present conditions. Conventional test tubes continue to represent the most desirable geometric form for storing samples. Machinery for withdrawing sample portions from such test tubes into containers for subsequent analysis of different sample portions is relatively complicated to construct and, therefore, not economically feasible.

To overcome some of the above enumerated shortcomings it has been suggested to insert into the test tube a plunger which includes a flexible flow tube communicating with the test tube interior and extending to the test tube exterior. By forcing the plunger into the test tube the sample is withdrawn through the flow tube. Such a test ice tube is disclosed in U.S. Pat. 3,355,098. However, the sample is not sealed from the exterior and the tube provides no substantial aid in test automation attempts since the required machinery would continue to be relatively complicated and expensive.

For an eifective, low cost automation of the sample handling it is, therefore, necessary to provide means enabling an automated, low cost distribution of the sample from the test tube to a plurality of containers. Thereafter, the containers can be automatically transported to automated analyzers and the like to etfect substantial laboratory cost reductions.

SUMMARY OF THE INVENTION The present invention provides a cover for test tubes and like vessels having an open end which seals the contents in the tube and permits repeated access to the tube interior for removal of all or part of the contents therefrom or for the introduction of contents therein. Briefly, the cover comprises a plug constructed of a resilient material for placement into and sealing of the test tube opening. The plug includes a pair of parallel spaced apart apertures which extend over the length of the plug and into which a generally U-shaped tubular member having parallel tubular sections connected by a semi-circular section is inserted. The tubular member fits snugly within the apertures so that the test tube interior is sealed from the exterior. Withdrawal of one tubular section from one of the apertures enables the connection of a source of positive or negative pressure to such aperture, and thereby, to the test tube interior for inducing a fluid flow via the tubular member into or out of the test tube.

In the preferred embodiment of the invention the tubular member is constructed of a flexible material such as plastic and the plug is provided with means positioning the tubular section Withdrawn from the aperture relative to the plug so that containers can be placed at a predetermined relative position with respect to the plug. Upon pressurizing of the interior of the test tube fiuid, such as serum, it is Withdrawn and discharged into the container. Similarly, a sample can be placed into the test tube by merely connecting the end of the tubular memher on the exterior of the test tube with a source of fluid and subjecting the tube interior to a vacuum until the desired fluid level in the test tube has been attained.

Test tubes fitted with a cover in accordance with the present invention lend themselves to the automatization of the sample handling in the laboratory. For example, the test tubes can be mounted in holders or the like and passed beneath a vacuum and/or pressure pump that is automatically engaged with the open aperture in the plug to withdraw the desired quantity of the sample from the test tube. The containers can be mounted on automatic conveyors for transport with sample identification to automated testing stations or analyzers so that the testing of blood samples and the like in laboratories can be substantial-ly fully automated. Substantial time savings as well as much less stringent requirements on the skill of the technician are obtained. Furthermore, the total sample size can be reduced since waste from spillage and unequal sample distribution, as commonly encountered during manual handling of the sample, are prevented.

After the sample has been distributed the test tube can again be closed by replacing the tubular section in the open aperture. The sample is thus again in a sealed container for storage or subsequent use. The sealing of the sample in the test tube, moreover, eliminates the heretofore encountered health hazard from diseased sample or the danger of a contamination of the samples from foreign substances that can enter the open test tube.

The cover of the present invention is of a simple construction and can be inexpensively mass produced. It is, therefore, a virtually essential aid in attempts to improve safety and automate the laboratory testing of blood samples and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective elevational view of a test tube closed with a cover constructed in accordance with the present invention;

FIG. 2 is a perspective elevational view similar to FIG. 1 and shows the test tube cover opened for withdrawing sample portions from the test tube;

FIG. 3 is an enlarged fragmentary side-elevational view, in section, of the upper portion of the test tube and illustrates its connection to a source of positive or negative pressure;

FIG. 4 is an enlarged perspective view of the plug illustrated in FIGS. 1 and 2;

FIG. 5 is an enlarged perspective elevational view similar to FIG. 4 but illustrates another embodiment of the plug;

FIG. 6 is a perspective view similar to FIG. 4 but shows still another embodiment of the plug;

FIG. 7 is a fragmentary, elevational view of the open end of a test tube constructed according to the invention; and

FIG. 8 is a plan view of the test tube illustrated in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, a test tube assembly 10 constructed in accordance with the invention comprises a test tube 12 having a cylindrical configuration, a closed bottom end 14 and an open upper end 16. The test tube includes graduations 17 over all or at least part of its length indicating volumetric quantities such as cm. to aid in determining the quantity of fluid in the tube from the fluid level. The open test tube end is closed with a cover or plug which includes a pair of spaced apart apertures 20, 22 through which a flexible U-shaped tubular member or flow tube 24 having a pair of substantially straight, parallel flow tube sections 26 and 28 interconnected by a circular flow tube section 30.

Referring to FIGS. 1 to 3, cover 18 is constructed of a resilient material such as rubber or plastic and com prises a substantially cylindrical body 32 extending into test tube 12 and fitting snugly against the test tube walls to provide a seal. A cap 34 is integrally constructed with the body and limits the depth to which the body can be pushed into the test tube. First aperture is substanially cylindrical over its length and has a diameter so that flow tube 24 fits snugly into the aperture and seals the aperture. Second aperture 22 includes a lower cylindrical portion 36 of a diameter equal to the diameter of first aperture 20 and an upper, outwardly flaring frustoconical portion 38. When straight sections 26 and 28 of flow tube 24 are disposed in apertures 20 and 22 the interior of the test tube is sealed.

Access to the test tube is provided by pulling flow tube section 28 upwardly until its end clears the second aperture. Thereafter, the tubular member can be rotated about straight section 26 or flipped over until section 28 extends beyond the periphery of test tube 12. The conical end of a nozzle 40 having a passageway 42 communicating with a source of positive or negative air pressure 44 is placed against the frustoconical portion 48 of second aperture 22. The application of positive air pressure to passageway 42 causes a corresponding pressure increase inside test tube 12 and forces fluid material in the test tube through flow tube 24 to the exterior of the test tube. Conversely, immersion of the outer free end of the flow tube in a fluid and the application of a negative pressure or vacuum to passageway 42 causes the filling of the test tube with the fluid.

Referring to FIGS. 1 through 6, means 45 for holding and positioning flow tube section 28 while disposed exteriorly of the test tube is provided to prevent it from hanging loosely, twisting about the axis of section 26 and to assure that it is positioned at a predetermined relative location when disposed exteriorly of the test tube. In one embodiment, illustrated in FIGS. 1, 2 and 4, the means comprises an oval or cylindrical member 46 having a pair of opposite substantially semi-circular longitudinal grooves 48 and 50 on its exterior. The grooves have a diameter about equal to the outside diameter of flow tube 24, have edges 52 which protrude slightly inwardly, and the member is constructed of a flexible material so that it can be placed between flow tube sections 26 and 28 and snapped onto the sections to thereby maintain the flow tube sections at the spacing of grooves 48 and 50. The oval member can be integrally constructed with cap 34 of plug 18, can be independent thereof or can be provided with a locating pin (not shown) to assure that the member is always placed in the same relative position with respect to the plug.

FIG. 5 illustrates another embodiment of plug 18. An elongate, substantially semi-circular sling or bar 54 is provided and has its ends connected to the periphery of cap 34. The sling, together with the cap periphery between the sling ends, defines an opening 56 through which flow tube section 28 can be extended when it is exterior-ally of the test tube. Sling 54 is preferably integrally constructed with plug 18.

FIG. 6 illustrates yet another embodiment of the tube holder which comprises a flange 58 extending radially outward of cap 34 and terminating in a generally vertically disposed holder 60 having opposing jaws or clamps 62 for the grasping and positioning of flow tube section 28.

Referring to FIGS. 7 and 8, holding means 45 can also be integrally constructed with test tube 12 to simplify the shape of plug 18 by providing a flange 64 that extends outwardly from the test tube. The flange includes slot 66 into which tubular member 24 can be slideably inserted. Alternatively, an aperture (not shown) can be provided in the flange through which the tubular member extends.

Test tube assembly 10 is used as follows. The test sample, say a blood sample, is placed into the test tube which is closed with plug 18 via tube sections 26 and 28 by applying a vacuum to aperture 22 until a sutficient sample is drawn into the test tube. Thus, the blood sample is sealed against contamination and against contaminating the surrounding atmosphere while the sample is placed into the test tube as well as thereafter replacing tube section 28 in aperture 22. Next the test tube is transported, preferably with a suitable conveyor (not shown), to beneath pressure nozzle 40. Tube section 28 is now withdrawn from aperture 22 and turned or flipped into engagement with tube holder 45. Flow tube 24 is raised until the lower end of flow tube section 26 is disposed above the red blood cell level, or, alternatively, tubular section 26 is dimensioned sufficiently short so that its lower end does not extend into the body of settled red blood cells and nozzle 40 is contacted with the frustoconical portion 38 of aperture 22. Thereafter, pressurized air or gas is passed into the test tube until the desired quantity of serum has been discharged from the end of tube section 28 disposed exteriorly of the test tube. This can be repeated as many times as necessary for the performance of the required tests and analyses. Thereafter the test tube is withdrawn from nozzle 40 and tube section 28 is replaced in aperture 22 to reseal the test tube for further use and/ or storage until the contents of the test tube can be discarded.

Withdrawal of the fluid in the above-described manner eliminates the need for tipping the fluid as here before necessary. An admixture of different fluid levels or a mixture of solids settled at the bottom of the test tube as encountered in the testing of centrifuged blood samples are thereby prevented. Moreover, graduations 17 on test tubes enable a quick and relatively precise measuring of the fluid quantity transferred into or withdrawn from the test tube. The need for elaborate measuring apparatus or for relying on the inherently inaccurate judgment of technicians for determining fluid quantities is thereby eliminated. Eflective, accurate and relatively inexpensive control and handling of the samples in laboratories is thereby assured.

I claim:

1. Apparatus for sealing an open end of a test tube and providing selective access into the tube comprising: a plug fitting snugly into the open end, the plug having a first opening and a second opening communicating the tube interior with the exterior, a conduit having first and second conduit sections axially extensible through the openings for placement of the ends thereof interiorly of the tube, at least one conduit section having a suflicient length to extend to adjacent a closed end of the test tube, the conduit being sized to snugly fit into the opening to seal the vessel interior from the exterior when the conduit extends through both openings, whereby removal of one of the sections from one of the openings and a pressurization or depressurization of the tube provides for a fluid flow between the interior and the exterior of the tube via the conduit.

2. Apparatus according to claim 1 including means positioning a conduit section removed from one of the openings substantially parallel to the other tube section on the exterior of the tube.

3. Apparatus for closing an open end of a test tube and for providing access to the interior of the tube while the open end is so closed comprising: a plug having a substantially cylindrical body constructed of a resilient material for placement into the open end of the test tube and sealing the test tube, the plug having first and second spaced apart apertures, each aperture being substantially parallel to the axis of the body and extending from one end thereof to the other for communicating the tube interior with the exterior, the first aperture having an enlarged, outwardly flaring outer portion and a cylindrical remainder, the second aperture having a cylindrical portion of a diameter equal to the diameter of the cylindrical remainder for insertion of an elongate cylindrical conduit of a suflicient length to extend to adjacent another closed end of the tube into the apertures and forming a snug, sealing fit between the conduit and the apertures, whereby removal of the conduit from one of the apertures and pressurization or depressurization of the tube interior through the other aperture effects a fluid flow between the interior and exterior by the tube via the conduit.

4. Apparatus according to claim 3 including means extending away from the body for grasping a section of the conduit disposed on the exterior of the tube while the section is removed from one of the apertures.

5. Apparatus according to claim 3 wherein the outwardly flaring portion is defined by a frustoconical wall.

6. Apparatus according to claim 4 wherein the means comprises a radially outwardly extending flange and open jaws constructed of a resilient material and dimensioned for releasably engaging the conduit.

7. Apparatus according to claim 4 wherein the means comprises substantially U-shaped band means extending away from the plug and having its ends connected to the plug to define an opening between an intermediate band means portion and the plug through which the section of the conduit can be extended.

8. Apparatus according to claim 4 wherein the means comprises an upright bar defining opposing, outwardly opening, parallel grooves dimensioned to grasp the section and retain the section in the grooves, the spacing between the grooves exceeding the spacing between the second aperture and the outermost periphery of the plug adjacent the second aperture so that one groove can be snapped onto a portion of the conduit adjacent the second aperture and the other groove can be snapped onto the section of the conduit disposed exteriorly of the tube for retaining the section in position.

9. A resealable test tube assembly permitting fluid transfers between the tube interior and the exterior comprising: a test tube terminating in a substantially cylindrical opening, a test tube cover having a cylindrical body constructed of a resilient material sealingly disposed in the test tube opening, the cover including a pair of spaced apart apertures extending over the length of the body and having like and constant cross-sections over at least part of their length, and a U-shaped flow tube having fluidly connected substantially parallel sections extending through the apertures and a cross-section to sealingly engage the body, whereby withdrawal of one of the sections from the test tube and the body enables a fluid transfer between the test tube interior and exterior via the flow tube by applying a pressure or vacuum source to the aperture from which the one section has been withdrawn.

10. Apparatus according to claim 9 wherein at least one of the sections has a suflicient length to extend substantially to a closed end of the test tube.

11. Apparatus according to claim 9 wherein the flow tube is constructed of a flexible material enabling the positioning of the one flow tube section on the exterior of the test tube, and including means for maintaining the one flow tube section in the same general orientation as the flow tube section disposed interiorly of the test tube.

12. Apparatus according to claim 9 wherein the aperture from which the one flow tube section has been withdrawn includes a tapered, outwardly flaring portion for engaging a conical member of the pressure or vacuum source.

13. Apparatus according to claim 9 including means limiting the insertion of the body into the test tube.

14. A resealable test tube assembly for fluid transfers between the tube interior and the exterior comprising a test tube defined by an open-ended, substantially cylindrical vessel and a flange positioned adjacent the open end and extending radially away from the vessel, the flange defining a cutout, a test tube cover having a cylindrical body constructed of a resilient material sealingly disposed in the vessel, the cover including spaced apart apertures extending over the length of the body and having like and constant cross sections over at least part of their lengths, and a flow tube having fluidly connected, substantially parallel sections extending through the apertures and a cross section to sealingly engage the body, whereby withdrawal of one of the sections from the test tube and the body enables a fluid transfer between the test tube interior and exterior via the flow tube by applying a pressure or vacuum source to the aperture from which the one section has been withdrawn, the cutout having a transverse dimension for releasably engaging the withdrawn flow tube section and positioning it substantially parallel to the vessel on the exterior of the v essel.

15. Apparatus according to claim 14 wherein the cutout in the flange defines a slot extending from a central portion of the flange to a periphery of the flange enabling a laterally slidable insertion of the flow tube into the slot.

References Cited UNITED STATES PATENTS 7/1963 Sager 23259 X 5/1965 Hesson 23-259 X 8 3,481,477 12/1969 Farr 23-259 X MORRIS O. WOLK, Primary Examiner 5 R. E. SERWIN, Assistant Examiner US. Cl. X.R. 

